Because it is an urban environment, the city of Long Beach is a suitable location to investigate the use of passive seismic data for subsurface imaging and velocity analysis at the reservoir scale. The dense, continuously recording Long Beach array is ideal for time-lapse analysis. We captured a variety of earthquake waveforms, generated both near to and far from the array, that could be used for tomographic imaging. We have also captured correlating energy at low frequencies using seismic interferometry techniques, which can also be used for tomographic imaging. Therefore, there are indications that seismic land data from an urban environment has the potential to be used for subsurface monitoring.